A sander is commonly used in profiling wood. A sander generally comprises a housing and a sanding plate mounted below the housing. A motor and a transmission are disposed within the housing. The sanding plate is connected to an output end of the transmission. Sanding paper is attached to the bottom of the sanding plate. The sanding plate is driven by the motor and when used, results in the sanding of a workpiece surface.
As shown in the prior art, a sander powered by a battery pack is convenient to carry and is easily adapted for use in different work situations. The battery pack is usually mounted at the rear of the sander so that the height of the sander is not increased. This arrangement results in the sander having a compact structure and small size, which allows the user to easily control the movement of the sander.
The battery pack at the rear end of the sander may be heavy. Although there are low weight battery packs on the market, the lighter battery packs do not provide the required satisfactory power for known sanders. As a result, a sander with a relatively high-power and heavy battery pack may be unbalanced because the high-power battery pack changes the center of gravity of the sander, and the sander is no longer balanced. Instead of being balanced, the center of gravity of the sander is moved closer to the rear, and as a result, when the sander is placed on a work table the sander is easy to flip over backwards. Also, the changed center of gravity may make control of the sander more difficult for a user.